Abstract:In the context of global carbon emission reduction and sustainable development, CO2 resource utilization has emerged as a focal point of intensive research. Among various transformation strategies, electrocatalytic CO2 conversion into high-value products offers distinct advantages, including mild reaction conditions, low energy consumption, and minimal secondary pollution, thereby alleviating environmental pressures. In particular, for urea synthesis, electrocatalytic C—N coupling offers a greener alternative to the traditional Haber-Bosch process, which requires high temperatures and pressures, by enabling ambient-condition production using CO2 and various nitrogen sources (e.g., N2, , NO). This approach facilitates CO2 resource utilization and effectively addresses the challenge of high energy consumption in conventional urea synthesis. Since this process involves multiple proton-electron transfer steps, the reaction mechanism varies significantly depending on the nitrogen source. For N2-based systems, the fundamental challenge lies in the efficient activation and cleavage of the N≡N triple bond, where the generation of *N=N intermediates critically determines the efficiency of subsequent C—N coupling. The coupling-hydrogenation pathway initiated by the formation of the *NCON intermediate exhibits favorable thermodynamics and a relatively low energy barrier for the initial C—N bond formation. Regarding , combined experimental and theoretical studies have identified multiple potential pathways. Among these, the coupling of *NH2 with *CO to form *CONH2 has been demonstrated as the most effective route, successfully facilitating urea formation while suppressing competing pathway leading to NH3 or N2. Although current research on the *NO-mediated reaction pathways remain limited, their application potential is promising. This pathway is expected to achieve higher Faradaic efficiency due to its lower N—O bond dissociation energy and a reduction potential compatible with the CO2 reduction reaction. However, it faces a significant limitation: NO exhibits oxidative instability in aqueous electrolytes and is consumed through homogeneous oxidation reactions. Addressing this issue requires sophisticated reactor design and operational strategies. Furthermore, all nitrogen source systems face a fundamental challenge regarding the precise control of competitive reduction processes. The hydrogen evolution reaction limits practical efficiency, while the over-reduction of nitrogen-containing intermediates to ammonia significantly compromises urea selectivity. This review categorizes electrocatalytic C—N coupling methods for urea synthesis into three types based on nitrogen sources (N2, , and NO) and systematically summarizes the corresponding reaction mechanisms and recent research progress, focusing on the diversity of reaction pathways, the generation and transformation of key intermediates, and the identification of optimal reaction pathways for different nitrogen sources. Finally, this review outlines the key challenges currently facing electrocatalytic C—N coupling and provides perspectives on future research directions, with the aim of providing theoretical guidance for advancing research in this field. Close-